This core will gather all of the psychometric and behavioral assessments for Projects I-III. It will evaluate 150 persons with autism, 125 controls, and more than 90 family members over a five year period with between 70 and 120 subjects evaluated each year (approximately 20 in Year- 05). Subject with autism will be screened on CARS, Vineland, CBCL, and PPVT, followed by the ADI-R and the ADOS-G. Preschoolers will get an EEG, and the school age group will get a Tanner evaluation and blood levels of estradiol and testosterone. Control groups will be screened with CBCL, Vineland, and SNAP-IV-C. Clinical levels on any of these will rule out the subject. The core instruments involve a history and physical and neuroexaminations, intelligence testing, (Binet, Bayley, and WIAT), three language tests and a language sample, executive function measures, and the ESCS for pragmatics and joint attention.